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| author | David Henningsson <coding@diwic.se> | 2021-05-15 09:15:33 +0200 |
|---|---|---|
| committer | Takashi Iwai <tiwai@suse.de> | 2021-05-17 16:02:44 +0200 |
| commit | 08fdced60ca08e34e316a3ab945636fcdfcbc973 (patch) | |
| tree | 2ebf36f380c9bafbb78b43bb32de7118c8f4d529 /include/sound/rawmidi.h | |
| parent | bac59054544ebdb89f05c5b9598ca9cb2dea72ce (diff) | |
| download | linux-08fdced60ca08e34e316a3ab945636fcdfcbc973.tar.bz2 | |
ALSA: rawmidi: Add framing mode
This commit adds a new framing mode that frames all MIDI data into
32-byte frames with a timestamp.
The main benefit is that we can get accurate timestamps even if
userspace wakeup and processing is not immediate.
Testing on a Celeron N3150 with this mode has a max jitter of 2.8 ms,
compared to the in-kernel seq implementation which has a max jitter
of 5 ms during idle and much worse when running scheduler stress tests
in parallel.
Signed-off-by: David Henningsson <coding@diwic.se>
Reviewed-by: Jaroslav Kysela <perex@perex.cz>
Link: https://lore.kernel.org/r/20210515071533.55332-1-coding@diwic.se
Signed-off-by: Takashi Iwai <tiwai@suse.de>
Diffstat (limited to 'include/sound/rawmidi.h')
| -rw-r--r-- | include/sound/rawmidi.h | 2 |
1 files changed, 2 insertions, 0 deletions
diff --git a/include/sound/rawmidi.h b/include/sound/rawmidi.h index 334842daa904..989e1517332d 100644 --- a/include/sound/rawmidi.h +++ b/include/sound/rawmidi.h @@ -81,6 +81,8 @@ struct snd_rawmidi_substream { bool opened; /* open flag */ bool append; /* append flag (merge more streams) */ bool active_sensing; /* send active sensing when close */ + unsigned int framing; /* whether to frame input data */ + unsigned int clock_type; /* clock source to use for input framing */ int use_count; /* use counter (for output) */ size_t bytes; struct snd_rawmidi *rmidi; |